Tumour necrosis factor-α contributes to improved cardiac ischaemic tolerance in rats adapted to chronic continuous hypoxia.

AIM: It has been demonstrated that tumour necrosis factor-alpha (TNF-α) via its receptor 2 (TNFR2) plays a role in the cardioprotective effects of preconditioning. It is also well known that chronic hypoxia is associated with activation of inflammatory response. With this background, we hypothesized that TNF-α signalling may contribute to the improved ischaemic tolerance of chronically hypoxic hearts. METHODS: Adult male Wistar rats were kept either at room air (normoxic controls) or at continuous normobaric hypoxia (CNH; inspired O2 fraction 0.1) for 3 weeks; subgroups of animals were treated with infliximab (monoclonal antibody against TNF-α; 5 mg kg(-1), i.p., once a week). Myocardial levels of oxidative stress markers and the expression of selected signalling molecules were analysed. Infarct size (tetrazolium staining) was assessed in open-chest rats subjected to acute coronary artery occlusion/reperfusion. RESULTS: CNH increased myocardial TNF-α level and expression of TNFR2; this response was abolished by infliximab treatment. CNH reduced myocardial infarct size from 50.8 ± 4.3% of the area at risk in normoxic animals to 35.5 ± 2.4%. Infliximab abolished the protective effect of CNH (44.9 ± 2.0%). CNH increased the levels of oxidative stress markers (3-nitrotyrosine and malondialdehyde), the expression of nuclear factor κB and manganese superoxide dismutase, while these effects were absent in infliximab-treated animals. CNH-elevated levels of inducible nitric oxide synthase and cyclooxygenase 2 were not affected by infliximab. CONCLUSION: TNF-α plays a role in the induction of ischaemia-resistant cardiac phenotype of CNH rats, possibly via the activation of protective redox signalling.

Involvement of PKCepsilon in cardioprotection induced by adaptation to chronic continuous hypoxia.

Continuous normobaric hypoxia (CNH) renders the heart more tolerant to acute ischemia/reperfusion injury. Protein kinase C (PKC) is an important component of the protective signaling pathway, but the contribution of individual PKC isoforms under different hypoxic conditions is poorly understood. The aim of this study was to analyze the expression of PKCepsilon after the adaptation to CNH and to clarify its role in increased cardiac ischemic tolerance with the use of PKCepsilon inhibitory peptide KP-1633. Adult male Wistar rats were exposed to CNH (10 % O(2), 3 weeks) or kept under normoxic conditions. The protein level of PKCepsilon and its phosphorylated form was analyzed by Western blot in homogenate, cytosolic and particulate fractions; the expression of PKCepsilon mRNA was measured by RT-PCR. The effect of KP-1633 on cell viability and lactate dehydrogenase (LDH) release was analyzed after 25-min metabolic inhibition followed by 30-min re-energization in freshly isolated left ventricular myocytes. Adaptation to CNH increased myocardial PKCepsilon at protein and mRNA levels. The application of KP-1633 blunted the hypoxia-induced salutary effects on cell viability and LDH release, while control peptide KP-1723 had no effect. This study indicates that PKCepsilon is involved in the cardioprotective mechanism induced by CNH.

Proline oxidase, a p53-induced gene, targets COX-2/PGE2 signaling to induce apoptosis and inhibit tumor growth in colorectal cancers.

Proline oxidase (POX), a flavoenzyme localized at the inner mitochondrial membrane, catalyzes the first step of proline degradation by converting proline to pyrroline-5-carboxylate (P5C). POX is markedly elevated during p53-induced apoptosis and generates proline-dependent reactive oxygen species (ROS), specifically superoxide radicals, to induce apoptosis through both mitochondrial and death receptor pathways. These previous studies also showed suppression of the mitogen-activated protein kinase pathway leading us to broaden our exploration of proliferative signaling. In our current report, we used DLD-1 colorectal cancer cells stably transfected with the POX gene under the control of a tetracycline-inducible promoter and found that three pathways which cross talk with each other were downregulated by POX: the cyclooxygenase-2 (COX-2) pathway, the epidermal growth factor receptor (EGFR) pathway and the Wnt/beta-catenin pathway. First, POX markedly reduced COX-2 expression, suppressed the production of prostaglandin E2 (PGE(2)) and importantly, the growth inhibition by POX was partially reversed by treatment with PGE(2.) Phosphorylation of EGFR was decreased with POX expression and the addition of EGF partially reversed the POX-dependent downregulation of COX-2. Wnt/beta-catenin signaling was decreased by POX in that phosphorylation of glycogen synthase kinase-3beta (GSK-3beta) was decreased on the one hand and phosphorylation of beta-catenin was increased on the other. There changes led to decreased accumulation of beta-catenin and decreased beta-catenin/TCF/LEF-mediated transcription. Our newly described POX-mediated suppression of proliferative signaling together with the previously reported induction of apoptosis suggested that POX could function as a tumor suppressor. Indeed, in human colorectal tissue samples, immunohistochemically-monitored POX was dramatically decreased in tumors compared with normal counterparts. Thus, POX metabolism of substrate proline affects multiple signaling pathways, modulating both apoptosis and tumor growth, and could be an attractive target to metabolically control the cancer phenotypes.

Proline oxidase activates both intrinsic and extrinsic pathways for apoptosis: the role of ROS/superoxides, NFAT and MEK/ERK signaling.

Proline oxidase (POX), often considered a 'housekeeping enzyme' might play an important role in apoptosis. We have shown that POX generated proline-dependent reactive oxygen species (ROS), specifically superoxide radicals, and induced apoptosis through the mitochondrial (intrinsic) pathway. In our current report, we used DLD-1 colorectal cancer cells stably transfected with the POX gene under the control of a tetracycline-inducible promoter and found POX-stimulated expression of tumor necrosis factor-related apoptosis inducing ligand (TRAIL), DR5 and cleavage of caspase-8. Importantly, apoptosis measured by flow cytometry was partially inhibited by Z-IETD-FMK, a specific inhibitor of caspase-8. These findings suggest that the extrinsic (death receptor) pathway also is activated by POX. Furthermore, the mechanism of this effect on the extrinsic pathway, specifically, the induction of TRAIL by POX, may be mediated by NFAT transcription factors. Additionally, POX expression also dramatically decreased phosphorylation of MEK and ERK, and the decrease was partially reversed by expression of manganese superoxide dismutase (MnSOD). Overexpression of constitutively active form of MEK, acMEK, partially blocked POX-induced apoptosis. These findings suggest the involvement of MEK/ERK signaling and further confirm the role of ROS/superoxides in POX-induced apoptosis. Combined with previously published data, we conclude that POX may induce apoptosis through both intrinsic and extrinsic pathways and is involved in nuclear factor of activated T cells (NFAT) signaling and regulation of the MEK/ERK pathway. It is suggested that, as a nutrition factor, POX may modulate apoptosis signals induced by p53 or other anti-cancer agents and enhance apoptosis in stress situations.

First direct observation of coulomb explosion during the formation of exotic atoms

A Doppler broadening of x-ray transitions from pionic nitrogen and muonic oxygen, which is attributed to Coulomb explosion of the molecules, has been observed by using a crystal spectrometer. Large linewidths indicate fast ionization of the molecules and a charge of (3-4)e for the accelerated fragments.

Characterization of the BRCA1-like immunoreactivity of human seminal plasma.

OBJECTIVES: The subcellular localization of the breast cancer susceptibility gene product BRCA1 has been controversial. Discrepant results have been reported during the past 3 years, partially because of the unavailability of highly specific reagents for BRCA1 protein. Our objective was to characterize the BRCA1-like immunoreactivity that is detected in human seminal plasma by using monoclonal and polyclonal antibodies that are supposedly specific for BRCA1 protein. METHODS: We used immunologic, chromatographic, and protein sequencing techniques to detect the immunoreactivity of BRCA1 in seminal plasma and to purify and partially identify the immunoreactive species. RESULTS: We present data indicating that two BRCA1 antibodies, SG-11 and D-20, which were thought to be free of cross-reactivities, strongly interact with proteins present in human seminal plasma. This cross-reactivity is detectable even at seminal plasma dilutions as high as 10(6)-fold, and it is effectively blocked by peptides that capture the binding site of either SG-11 or D-20 antibodies. Purification and characterization of the immunoreactive compound revealed that this consists of a macromolecular complex that contains semenogelins. The D-20 polyclonal antibody was found to cross-react with purified semenogelins I and II; the SG-11 monoclonal antibody appeared to recognize a component of the macromolecular complex that was not semenogelin. CONCLUSIONS: Our data demonstrate that the BRCA1 antibodies SG-11 and D-20 strongly interact with seminal plasma proteins and are not highly specific for BRCA1 protein. It is thus suggested that BRCA1 antibodies should be used with caution until reagents free of interference are developed and evaluated. In light of the very high cross-reactivity of the two antibodies with seminal plasma proteins, we recommend that new BRCA1 antibodies should be examined for cross-reactivity with seminal plasma proteins to verify specificity.

Prostate specific antigen molecular forms in breast cyst fluid and serum of women with fibrocystic breast disease.

We have analyzed matched serum and breast cyst fluid samples for total PSA from 148 patients with fibrocystic breast disease. We have also determined the molecular forms of PSA (free PSA and PSA bound to alpha1-antichymotrypsin) in 78 breast cyst fluid samples. We found that total PSA can be detected in all cyst fluids and in about 75% of female sera. The median total PSA concentration in breast cyst fluid (bcf) is about 30 times higher than the median in the corresponding sera. Breast cyst fluid and serum PSA are not correlated with each other. Total serum PSA is inversely associated with patient age but the inverse association between bcf PSA and age is weak. Lower total PSA in bcf was seen in women who breast feed, and higher bcf PSA is associated with multiple cysts. Type I cysts (with a high K+/ Na+ ratio) tend to have higher total PSA than Type II cysts. All but three of the fractionated cyst fluids (75/78; 96%) had free PSA as the predominant molecular form. The most consistent finding of our study was the positive association between the cyst fluid K+/Na+ ratio and the free to bound PSA ratio. This association was confirmed by Spearman correlation as well as by Wilcoxon and chi-square analysis. Secretory/apocrine cysts (Type I) tend to have more total PSA and proportionally more free PSA than transudative/flattened cysts (Type II).

Quantification of pepsinogen C and prostaglandin D synthase in breast cyst fluid and their potential utility for cyst type classification.

OBJECTIVE: To quantify pepsinogen C (PEPC) and prostaglandin D synthase (PGDS) in breast cyst fluid and examine if these two parameters can be used for breast cyst type classification. DESIGN AND METHODS: We quantified PEPC and PGDS in 92 and 50 breast cyst fluids, respectively, using previously established immunofluorometric procedures. We then examined if the levels of PEPC or PGDS correlate with the type of cyst or with other clinicopathological variables. RESULTS: Quantitative analysis of the breast cyst fluids indicated that PEPC is present in all cyst fluids at various concentrations ranging from 3 to 31,000 ng/mL. PGDS positivity was confined to 30% of the cyst fluids. PEPC and PGDS levels were correlated with the breast cyst fluid cation ratio and were associated with the type of the cyst. Increased PEPC levels in breast cyst fluids were significantly correlated with a > or = 1.5 K+/Na+ ratio and were associated with the secretory/apocrine type of cyst (Type I) (p = 0.011). Immunoreactive PGDS levels were highly correlated with a low cation ratio and were associated with the transudative/flattened type of breast cyst (Type II) (p = 0.0003). A weak association was observed between PEPC levels in breast cyst fluid and menopausal status (p = 0.093). No significant associations were observed for either PEPC or PGDS concentration in breast cyst fluid and number of cysts, recurrence of the disease, family history of breast cancer, number of children, abortion, and breast feeding. CONCLUSIONS: Quantification of PEPC and PGDS in breast cyst fluid may be useful in the subclassification of cyst type in patients with gross cystic disease.

Stimulation of phosphoinositide kinases by thrombin is restricted to the plasma membrane in platelets.

This study was based on the hypothesis that lipid kinases in the different subcellular fractions would be differently affected by thrombin-treatment of platelets prior to subcellular fractionation. When using our previously reported method for subcellular fractionation on Percoll self-generated gradients, marker enzymes were detected as previously described. Stimulation of intact platelets with thrombin induced increased activities of PtdIns 4-kinase, PtdIns(4)P 5-kinase and PtdIns(4,5)P(2) 3-kinase in the plasma membrane fraction. PtdIns 4-kinase was also detected in internal membranes but was not modified by thrombin. We conclude that the production of phosphoinositides phosphorylated on the D3 and D5 positions of the inositol ring is restricted to the plasma membrane and that only the enzymes that are present in, or relocated to, the plasma membrane when platelets are activated are stimulated by thrombin.

Immunofluorometric assay of pepsinogen C and preliminary clinical applications.

We developed mouse monoclonal antibodies (Abs) against pepsinogen C with highly purified antigen isolated from gastric mucosa. The Abs were used to construct a two-site sandwich-type assay for pepsinogen C with time-resolved fluorometry as a detection technique. The assay has a detection limit of 0.1 microgram/L and is precise (within-run and day-to-day CVs < 11%). We used this assay to measure pepsinogen C in seminal plasma, breast cyst fluid, amniotic fluid, male and female serum, serum from patients with prostate cancer, urine, breast tumor cytosolic extracts, breast milk, and cerebrospinal fluid. Highest pepsinogen C concentrations were in seminal plasma, followed by breast cyst fluid and amniotic fluid. We found no correlation between prostate-specific antigen concentrations and concentrations of pepsinogen C in serum of prostate cancer patients, and concluded that this marker is not useful for either diagnosing or monitoring prostatic carcinoma. The availability of a highly sensitive, reliable, and convenient method for quantifying pepsinogen C will allow investigations into the possible diagnostic value of this analyte in various clinical conditions, including benign breast diseases, breast cancer, fertility, and pregnancy.

[Transitions in public health from the legal perspective]. / Der Wandel des Gesundheitswesens im Spiegel des Rechts.

The rules and regulations of the health system reflect the basic ideas of the health system itself. Taking a closer look at the regulations, we encounter the increasingly dominating idea of autonomous responsibility of the health services' clients. On the other hand, however, we find many regulations that express the lack of confidence in the health consumer's ability to make proper judgements regarding offers made by certain health providers. Thus, the whole health system is as ambivalent as the whole society. Today, no profound basic ideas seem to exist, with one exception: the economic power over the demands of most of the people.

Molecular forms of prostate-specific antigen in the serum of women with benign and malignant breast diseases.

Using a highly sensitive immunofluorometric procedure, we measured the total prostate-specific antigen (PSA) concentration in 632 sera obtained from female blood donors and women with idiopathic hirsutism, breast cancer or benign breast diseases. A total of 50 sera with total PSA > 15 ng l(-1) were fractionated by high-performance liquid chromatography (HPLC) in order to resolve the two immunoreactive molecular forms, i.e. free PSA (approximately 30 kDa) and PSA bound to alpha1-antichymotrypsin (PSA-ACT, 100 kDa). We found that breast cancer patients have presurgical serum total PSA levels similar to those of blood donors. Total serum PSA concentration decreases with age in women with idiopathic hirsutism, in cancer patients and in patients with benign breast diseases. The major molecular form of PSA in the serum of all normal and hirsute women (n = 15) is PSA bound to the proteinase inhibitor alpha1-antichymotrypsin. The major molecular form in 44% of presurgical cancer patient sera is free PSA. A total of 58% of benign breast disease patients also have in their serum mainly free PSA. We conclude that about half the patients with breast cancer or benign breast diseases have free PSA as the major molecular form in their serum, whereas patients without breast pathologies (normal blood donors, idiopathic hirsutism) have PSA bound to alpha1-antichymotrypsin as the major molecular form. The ratio of PSA/PSA-ACT may have value as a simple biochemical test for diagnosis of breast pathologies including breast cancer.

Altered expression of PDE1 and PDE4 cyclic nucleotide phosphodiesterase isoforms in 7-oxo-prostacyclin-preconditioned rat heart.

The stable prostacyclin derivative, 7-oxo-prostacyclin, exhibits a delayed, long-lasting cardioprotective effect, which is accompanied by an increase in cyclic nucleotide phosphodiesterase (PDE) activities restricted to the Ca2+-calmodulin-dependent (PDE1) and cyclic AMP-specific phosphodiesterase (PDE4) activities. Mammalian PDEs form a large multi-gene family with differential expression occurring in a cell- and tissue-specific manner. The aim of this study was to identify which isoforms of PDE1 and PDE4 are present in the hearts of control and 7-oxo-prostacyclin treated rats. Using RT-PCR analysis, we were able to identify in control rat hearts transcripts for PDE1C, but not for either PDE1A or PDE1B within the three-gene PDE1 family. Within the four-gene PDE4 family we detected, by generic RT-PCR analysis, transcripts for PDE4A, PDE4B and PDE4D, but not PDE4C. Using RT-PCR primers for specific splice variants, we identified transcripts for PDE4B1, PDE4B2, PDE4B3, PDE4D1, PDE4D2 and PDE4D3 in hearts from the control animals. Immunoblotting of hearts from the control animals for PDE4 forms allowed us to identify a 98-kDa PDE4A species, 68-kDa band representing PDE4D1/2 and a 95-kDa species indicative of PDE4D3. In the hearts of treated animals, 48 h after a single 50 microgram/kg dose of 7-oxo-prostacyclin, a profound increase in transcript levels was seen for both PDE1C and PDE4B3 together with a slight elevation for PDE4B1. No change in PDE4A transcripts occurred, which was consistent with a lack of change indicated in immunoblotting analyses. In contrast, 7-oxo-prostacyclin treatment caused decrease in transcript levels for PDE4D, which was confirmed by immunoblotting and shown to be due to a reduction in the levels of PDE4D3 and also in PDE4D1/D2. Thus, treatment of animals with 7-oxo-prostacyclin initiated profound isoform-specific changes in PDE expression in the myocardium which, presumably, underpin the increased PDE activity.

alphaIIb beta 3-integrin mediated adhesion of human platelets to a fibrinogen matrix triggers phospholipase C activation and phosphatidylinositol 3',4'-biphosphate accumulation.

This study focused on the variations in phosphoinositide metabolism depending upon alphaIIbbeta3-integrin/fibrinogen interaction without previous activation of platelet agonist receptors. We found that adhesion of resting human platelets to immobilized fibrinogen stimulates phosphatidic acid production and a concomitant decrease in phosphatidylinositol 4',5'-bisphosphate. These results, and the absence of a transphosphatidylation reaction, argue in favor of the activation of a phospholipase C. Moreover, we observed the accumulation of phosphatidylinositol 3',4'-bisphosphate in adherent platelets as a consequence of the activation of a phosphatidylinositol 3-kinase. This effect was inhibited by ADP scavengers. Our results demonstrate that in adherent platelets, whereas phosphatidylinositol 3-kinase activation is controlled by both alphaIIbbeta-integrin engagement and released ADP, phospholipase C stimulation is triggered only by alphaIIbbeta-integrin/fibrinogen interaction.

Long lasting anti-adrenergic effect of 7-oxo-prostacyclin in the heart: a cycloheximide sensitive increase of phosphodiesterase isoform I and IV activities.

Evidence is accumulating that 7-oxo-prostacyclin (7-oxo-PGI2) induces a delayed indirect anti-adrenergic and cytoprotective effect on the myocardium, the mechanism of which is still unclear. To demonstrate that a single application of 7-oxo-PGI2 (50 micrograms/kg i.m.) 48 h prior to starting experiments attenuates the isoprenaline inducible inotropic response and accumulation of cAMP, isolated hearts of pretreated animals were perfused in the Langendorff mode with and without isoprenaline (1 to 100 nM). The late anti-adrenergic effect of the drug was manifested by a significant attenuation in the elevation of cAMP levels as well as in contractile force development. This effect was not due to changes in cAMP generation as there were identical beta 1-adrenoceptor densities and affinities (as calculated from [3H]-CGP binding studies), Gi and G alpha s protein patterns (as taken from Western blots) as well as adenylyl cyclase activity measurements in the hearts studied. The anti-adrenergic potency of 7-oxo-PGI2, however, was found to be related to a significant rise in cyclic nucleotide hydrolysis by phosphodiesterase (PDE). Using the fast-performance liquid chromatographic separation for PDE isoforms, a significant increase in the activity of PDE isoforms I and IV (260 +/- 28 vs 110 +/- 12 pmol cGMP/min x enzyme fraction and 77 +/- 11 vs 34 +/- 3 pmol cAMP/min x enzyme fraction, respectively) was found in the solubilized fraction of cardiac membranes in comparison to untreated controls; PDE IV activity was also increased in the cytosolic fraction (106 +/- 14 vs 65 +/- 6 pmol cAMP/min x enzyme fraction). The hypothesis that the delayed anti-adrenergic effect of 7-oxo-PGI2 is initiated by an induction and accelerated synthesis of PDE I and IV in the heart is underlined by the fact that cycloheximide suppresses completely both the rise in PDE activities and the anti-adrenergic effects studied. It is suggested that an inducible predominance of cAMP degradation over its generation may be of relevance in processes related to heart protection.